There will always be a need for data on real incomes at constant prices in order to make macroeconomic comparisons for convergence in income studies, regional inequality and investment purposes. One is faced with extrapolating sparse time series data across space and there have been attempts to do this but the main problems are that the existing attempts only make use of specific benchmarks from the International Comparison Program (ICP) and does not provide measures of reliability in the form of standard errors. This study paper seeks to improve on the current estimates; in terms of their efficency and improve on reliability by making use of all the benchmark data from the ICP by producing standard errors for the estimates. Firstly, a simple ad hoc approach to construct a panel of real incomes along with the associated standard errors. The second approach is an econometric approach which utilises a state space form representation. It is this representation that the Kalman filter and smoother will be applied to produce real income estimates at constant prices for the OECD countries covering the time period 1971-2005. This thesis will be an extension of the work performed by Rao, Rambaldi & Doran (2009) and the estimates of real income at constant prices will be compared with those provided by the Penn World Tables (PWT 6.3), World Development Indicators and Angus-Maddison series.